Pictured above is a weathering style called honeycomb weathering. Honeycomb is a type of differential weathering that produces a Swiss cheese appearance on the rock’s surface that can be quite striking. This example is from a sandstone outcrop (Prairie Grove member) at Devil’s Den State Park in northwest Arkansas.
Honeycomb weathering has been observed in many rock types, from igneous to sedimentary, forming in wet and dry environments. It has even been noted in man-made structures. Despite being common, the causes of honeycomb weathering are poorly understood. Some studies have linked its formation to exposure to salt in coastal regions, but that doesn’t explain its occurrence in north Arkansas.
In this instance, some clever bats have taken advantage of one of the pits in the rock and are using it as a sleeping shelter.
For more views of honeycomb weathering click here.